code: def test_unit_norm(self):
      constraint_fn = constraints.UnitNorm()
      output = constraint_fn(get_example_array())
      output = backend.convert_to_numpy(output)
      l2 = np.sqrt(np.sum(np.square(output), axis=0))
      self.assertAllClose(l2, 1.0)
  
file_path: keras/keras/constraints/constraints_test.py
imports: import numpy
  from keras import backend
  from keras import constraints
  from keras import testing
label_desc: Use image node_id 3 for calling the ConstraintsTest obj's underlying member method code with example usage: obj.test_unit_norm() without return types